Electric measuring apparatus



' 'rsUTomU' UMEZAWA, on

ELEC RIC MEASURINGQAEPARATUS; l: f l ,1 7

7 Application filed July 3, 1922, ,S eria1 No 572,7 1$, ma spa Septemberfe 1921. a,

-- i Myjr'invenfidn fl testoelectric measuring 7 apparatus and moreparticularly to an elec tric measuring lnstrument arranged toserve fora;plurality of uses, 7 a

' Although my invention is applicable for various uses,,its primaryobject is to provide a .simple vand convenient instrument for measuringtemperatures by what is known as the exploring coil method. By exploringofza coil or conductor having a known te1nperature coefficient whichcoil iis exposed to the temperature to'be measured. 7 Thus ofl sauce ofa coil or-coils embedded therein and indicatin the result on anelectrical instru- 1 The featuresoit tentinies the temperature ofelectrical apparatus isdetermined bymeasuring the resist- V ment calirated to read directly intemper- ,aturevunits. In such method itisdesirableand often necessary to subject the exploring coil to the samevoltage. or curren't'each time a reading is. taken. flhus, ordinarily,two electrical instruments are necessary, one,

-;for;-measur ing the current or voltage to- "which; the 5exploring.coil is subjected and the; other for measuring or indicating in formeasuring potentials and both of which are used ina' difierential mannerfor measur ;-ing .temperatures. Other advantagesjof my invention willbe, pointed out as the descriptioniproceedsi g "lieve b05116 novel andpatentable" will be "pointed outin the claims appended hereto.

The details of 'constructionjan'd theory of operation of; my improvedmeasuring appa- V ratus will-ynowbe explained in connection with theaccompanying drawings in whichcoil method I mean the method ofmeasuring; temperatures. by -measuring vthe resistances my inventionwhich I: be;

havingjscales fo ncimtiiigebt ii the voltage andfthe temperaturejbymeans of) a single pointer 3, the two: scales fbeing are ranged as,shown'inFigifig The'pointer '3 6 7 j whichcoils are connectedjin'Qpp0$itj n,

is connected I to itwo moving coils 4 and/l resistancefi is connected inserieswith coil Theftwo resistances and 6 will,have tems the temperatureof which it is desired ftoj determine, Embedded-in the machine is anexploring coil 8 having a known. temper-' provided for. furnishingithemeasuring cur 4asis also a'resistance 6 when the instru -v rsjt mentisto be used for measuring, voltages. 7' Y I 'perat-ure'coeflicients equalto or substantially equal to zero. The construction of'the apflf 1 1paratus is not'restrictedto having"both'of. Y Y

movahle butymayhave rent andan adjustable resistance. v1O forob Itainingthe correct voltage 'Adoublethrow. yswitch lI-haVing. middlepoints connected to the source-9 isadapted," when thrown to" the uppercontacts, to connect the. source 9Iin f serieswithresistance ,10, coil 4ofinstltument- Q u 1 and the'ex ploring coil 8. 7 In'the upperflflPosition of switch 11 an auxiliarycontact-12 1 v thereonicooperates withstationary contacts to close a circuit connected between resistf ances.5 and 6 ofinstrume'nt ,1 and th'e line side ofexploring coil 8."Preferably a three- I pole plug, switch 13 *dperating withplug ratus.Where a plurality of exploring: coils areprovidedl the plug switch :13maybe f arranged to; connect anyj particular coil to the measuringinstrument i in a well understood manner. When the fvswitchi j 1 1; 7 isthrown down it'connects the source 9' across the-Volta e measurin coil L-and resistances l V b i i. i 1 i i 11 f socket 14 is provided forjdisconneeting; the a resistance coil 8 fromtherest of the; appar" TOKYO,JAPAN, ASSIGNQR ToGEnERAL ELECTRIC COMPANY-,5 AcoRPonATIoN orivnw YORK.i

ature coefficient A source voi potential 9 iis 5 and 6 0f "theinstrument l ;The direction of current through the variouscircuits with!the switch 11 down. is indicated by thesingle arrows andwiththeswitchl1up by the dou:- ble arrows. The instrument will be carefully,

Fig.-.l};illustrates the electrical connections of ,a .combinedvoltmeterand thermometer V when'co'nnected for use; F igz2'illu'strates amodified vconnection diagram for my proved instrument and Fig. ,3fis aperspeca? tiveview showingthe essential parts of the instrument. of I fv -aReferring, now to the drawings, ,in which like a parts are vdesignated by like numerals throughout 1 indicates a com binationvoltmeter *and electric thermometer 'ploring coil andfthe'adjustableresistance lO will be graduatedbefore hand so that by lll g h esi ancthereof the correct! l Voltage for usingqtheinstrument as jan electrioth'ermometenmay be obtained for 'difier; 1B

calibrated with-thelresistance ;8 of the ex m i graduation system.

ploring coil, a sourceof supply, switching means for connecting one ofsaid windings in series with said exploring coil and said source ofsupply and the other winding across said exploring coil in one positionof said switching means and for connecting only one of said 0011s inserles with said cah:

brating resistance to said source of supply in another position of saidswitching means,

the instrument being designed and'calibrated to-indicate the temperature.of the'exploring coil in the first mentioned position of 1 said.switching means and to indicate the voltage of the source of supply inthe second mentioned position of said switching means. 4.'An electricmeasuring instrument having a moving element, a pointer on said movingelement, a scale with which said pointer cooperates, said scale beinggraduated in two different systems ofunits, a torsional spring forcontrolling the movement of said moving element, two energizing windingsfor said instrument, connections for energizing only one of saidwindings forproducing a deflection of said pointer corresponding to oneof said graduation systems and con nections for energizing both ofsaidwindingsiin opposition to produce a deflection of said pointercorresponding to the other ture indicating instrument ofthe type adaptedto be use d'in connection with a'sourceof potential forindicating thetemperature of an exploring coil, a source of potential, a

temperature responsive. explorlng coil, a

side of said switch, circuit connections, assothe middle points of saidswitch, saidtwoway switch being thus adapted in one position to connecta portion of the exciting winding of said instrument ,to said source of,potential for measuring the-same, and in the other position to connectall of" the ex source of potential, variable resistance" and exploringcoil, in a manner to subject said coil and instrument to, the correctpotential for causing said instrument to indicate the temperature ofsaid coil.- v, I

In witnesswhereof, Ihave hereunto set my hand this thirteenth(13'th) dayof June, 7 ii 4.19 2. y p v t Q TSUTOMU UM 5. In. combination, anvelectric tempera- 50. 'citing winding of said instrument .to the

